'Peacemaker' immune cells could help treat diseases ranging from type 1 diabetes to neurodegeneration by restoring immune tolerance, according to a new paper in Frontiers in Science. The research highlights the potential of regulatory T cells (Tregs), originally defined as 'suppressor' cells that stop other immune cells from attacking the body, as 'living drugs' that could eventually be adapted to target many diseases with an inflammatory component.
The approach aims to tailor Treg therapies to specific diseases and tissues, supporting more precise control of immune responses. In autoimmune diseases and transplant rejection, Tregs could help shift treatment from broad immunosuppression toward restored immune tolerance and longer-term disease control. Joint lead author Dr. Fred Ramsdell, who won the 2025 Nobel Prize for Physiology or Medicine for his discoveries around immune tolerance and is also a co-founder and advisor to Sonoma Biotherapeutics, said, "With emerging genetic engineering and smart combination approaches, we're on the cusp of transforming how immune tolerance is restored and maintained. This really is only the beginning."
Researchers are investigating Tregs in a range of conditions linked to dysregulated immune tolerance including autoimmune diseases, chronic inflammation, cancer, severe COVID-19, neurodegeneration, metabolic disease, fibrosis, aging, pregnancy-related disorders, and autoimmunity. However, the role of Tregs differs across diseases; while they can suppress damaging inflammation in some cases to prevent autoimmune or degenerative conditions, cancers may exploit these same mechanisms to evade attack by the immune system. The paper describes how next-generation engineered Treg therapies could be designed either to restore or selectively disrupt tolerance depending on disease context.
Current standard care for autoimmune conditions and transplant rejection typically focuses on suppressing the immune system with powerful drugs—often targeting dangerous responses after tissue damage has occurred. Restoring immune tolerance rather than simply managing symptoms is therefore highly appealing. Early evaluations of Tregs have shown good safety profiles along with early signs of clinical benefit.
Dr. Ramsdell said, "Ultimately success will come down to precision: the right Treg delivered in the right way to the right tissue at the right time. That's the foundation that could extend tolerance-based medicine across an extraordinary range of human diseases." Maximizing impact depends on enhancing Treg function through new engineering tools allowing development of off-the-shelf therapies as well as gene-based approaches programming these cells inside patients.
Co-author Prof. Qizhi Tang from University of California San Francisco said, "The technical foundations have been laid and we may soon be able to transform treatment from broad immunosuppression to restoring true precision tolerance." Co-author Prof. Megan Levings from University of British Columbia and BC Children's Hospital Research Institute said, "With continued investment, cell-based therapies like Tregs could become a new pillar of medicine—standing alongside small molecules, biologics, and gene therapies—and unlocking treatments for diseases once thought incurable."
